Russia says it has provided a surface-to-air missile system to Syria, following the downing of a Russian reconnaissance plane off Syria.
Since 2000, Israel has been annual discreetly training and testing maneuvers created to defeat missile systems Russian Federation has deployed in the Middle East.
Iran's Revolutionary Guard launched six ballistic missiles as well as drone bombers toward Syria's Deir el-Zour province on Monday, targeting Islamic State militants it blamed for an attack on a military parade in Iran last month.
Russia, a key ally of Syrian President Bashar al-Assad, joined the seven-year war in 2015.
Sergei Shoigu said in televised remarks Tuesday that Russian Federation has delivered four S-300 launchers along with radars and support vehicles.
The system consists of 49 components, including radar, control vehicles and launchers.
He said the integration of Russian and Syrian air defense assets will be completed by October 20.
The US State Department said it could not confirm Russian Federation had delivered the systems to Syria, but that it would be a "concern" if it had.
The Il-20 was hit about 35km (22 miles) from the Syrian coast as it was returning to Russia's Hmeimim airbase near the north-western city of Latakia.
In addition to the Russian and Syrian air forces, warplanes from the US-led coalition fighting IS have also been carrying out bombing raids on Syria since September 2014.
Prime Minister Benjamin Netanyahu on Friday described Russia's move as "irresponsible". Iran has dismissed US demands that it leave Syria. He expressed confidence that Syria would be able to defend its air space against Israeli aggression.
But now clearly Putin is in the driver's seat and showed himself unmoved by Israeli threats to continue to act in Syrian territory even after the S-300 gets installed.
Israel has attacked targets in Syria more than 200 times and the USA has twice fired large salvos of Tomahawk Cruise missiles into the country.
In that time, only one Israeli jet is known to have been shot down - an F-16 which crashed in northern Israel.
Russian Federation said Tuesday it had completed delivering the S-300s.
The more capable S-300s could aide Syrian air defenses in targeting USA jets that operate in the region. They have a range of 5-150km (3-93 miles) at a maximum altitude of 27-30km (17-19 miles).